Projects

Memory
Create a game in which you memorise and repeat random
colour sequences

Step 1 Introduction

In this project, you will create a memory game in which you have to memorise and repeat a random sequence of colours!
What you will make

What you will learn

How to add sound to your Scratch project
How to create and use lists to store data
How to create and use custom blocks for repeating code

What you will need

Hardware
A computer capable of running Scratch 3
Software
Scratch 3 (either online (https://rpf.io/scratchon) or offline (https://rpf.io/scratchoff))
 Additional information for educators
You can find the completed project here (https://rpf.io/p/en/memory-get).
Step 2 Create a colour sequence

First create a character that can display a random sequence of colours.

Open a new Scratch project.

Online: open a new online Scratch project at rpf.io/scratch-new (https://rpf.io/scratch-new).

Offline: open a new project in the offline editor.

If you need to download and install the Scratch offline editor, you can find it at rpf.io/scratchoff (https://rpf.io/
scratchoff).

Choose a character sprite and a backdrop. You could use the ballerina, but your character doesn’t have to be a
person, they only need to be able to show different colours.

Your game should use a different number to represent each colour:

1 = red
2 = blue
3 = green
4 = yellow
 Give your character four costumes that have different colours, one costumes for each of the four colours shown
above. Make sure that your coloured costumes are in the same order as the list above.

If you want, you can use the color a shape tool to fill parts of the costume with a different colour.

Next, add a list for storing the random sequence of colours that the player has to remember.
Create a list called sequence. Only the character sprite needs to see this list, so you can select For this sprite
only when you create the list.

Make a list

Click on Make a List under Variables.

Type in the name of your list. You can choose whether you would like your list to be available to all sprites,
or to only a specific sprite. Click OK.

Once you have created the list, it will be displayed on the stage, or you can untick the list in the Scripts tab
to hide it.

Click the + at the bottom of the list to add items, and click the cross next to an item to delete it.
 New blocks will appear and allow you to use your new list in your project.

You should now see lots of new code blocks for using lists. The empty list should be visible in the top left-hand corner of
the Stage.
Each colour has a different number, so you can choose a random colour by randomly choosing a number and adding it to
the list.

Add this code to the character sprite to choose a random number and add it to sequence:

when clicked

add pick random 1 to 4 to sequence

Test your code. Check that, each time you click the flag, a random number between 1 and 4 gets added to the list.
Can you add code to your program to generate five random numbers at once?

I need a hint
This is what your code should look like:

when clicked

delete all of sequence

repeat 5

add pick random 1 to 4 to sequence

Each time a number gets added to the list, the character should change its costume so the costume’s colour
matches the number. Put these blocks into your code immediately below where a random number is added to
sequence:

switch costume to item length of sequence of sequence

wait 1 seconds
Step 3 Add sound

Test your project a few times. Do you notice that sometimes the same number is chosen twice (or more) in a row,
which makes the sequence harder to memorise?

Can you make a drum sound play each time the character sprite changes costume? And how about a different drum sound
for each colour?
Add the Music extension to your project so you can use the play drum block.

How to add the Music extension

To use the Music blocks in Scratch, you need to add the Music extension.

Click on the Add extension button in the bottom left-hand corner.

Click on the Music extension to add it.

The Music section then appears at the bottom of the blocks menu.
The code that plays the drum is very similar to the code that changes the character’s costume.

I need a hint
Here is how your finished code should look:

when clicked

delete all of sequence

repeat 5

add pick random 1 to 4 to sequence

play drum item length of sequence of sequence for 0.25 beats

switch costume to item length of sequence of sequence

wait 1 seconds
Step 4 Repeat the sequence

Now you’re going to add four buttons the player has to press to repeat the colour sequence.

Add four new sprites to your project to represent the four buttons.
Edit the new sprites’ costumes so that there is one sprite in each of the four colours
Put the sprites in the same order on the stage as the costumes: red, blue, green, yellow

Add code to the red sprite so that, when the sprite is clicked, it broadcasts a ‘red’ message to the character
sprite:

when this sprite clicked

broadcast red

A broadcast is like a message announced over a loudspeaker, which you can for example hear in schools or supermarkets.
All of the sprites can hear the broadcast, but only the sprite whose job it is to respond will do something.

Add similar code to the blue, green, and yellow sprites to make them broadcast messages about their own
colour.

Do you remember that the broadcast is like a loudspeaker message? You will add code to make it the character sprite’s
job to respond to the broadcast messages.
When your character sprite receives the message red, the code should check whether the number 1 is at the
start of the sequence list (which means that red is the next colour in the sequence).
If 1 is at the start of the list, the code should remove the number from the list, because the player remembered
the correct colour. Otherwise it’s game over, and the code needs to stop all to end the game.

when I receive red

if item 1 of sequence = 1 then

delete 1 of sequence

else

say Game over! for 1 seconds

stop all
 Add to the code you just wrote so that a drum beat also plays when the character sprite receives the correct
broadcast.

I need a hint

Here is the code you will need to add:

when I receive red

if item 1 of sequence = 1 then

play drum (1) Snare Drum for 0.25 beats

delete 1 of sequence

else

say Game over! for 1 seconds

stop all

Duplicate the code you used to make your character sprite respond to the message red. Change the duplicated
code so that it sends the message blue.

When the sprite responds to the message blue, which bit of code should stay the same, and which bit should change?
Remember that each colour has a corresponding number.
 Change the character sprite’s code so that the character responds correctly to the blue message.

I need a hint
Here is how your code should look for the blue broadcast.

when I receive blue

if item 1 of sequence = 2 then

play drum (2) Bass Drum for 0.25 beats

delete 1 of sequence

else

say Game over! for 1 seconds

stop all

Duplicate the code again twice (for the green and yellow buttons), and change the necessary parts so that the
character responds correctly to the new broadcasts.

Remember to test the code! Can you memorise a sequence of five colours? Is the sequence different each time?
When the player repeats the whole colour sequence correctly, the sequence list is empty and the player wins. If you want,
you can also display some flashing lights as a reward once the sequence list is empty.
Add this code to the end of your character’s when flag clicked script:

wait until length of sequence = 0

broadcast won and wait

Switch to the Stage, and import the drum machine sound or another sound you like.

Adding a sound from the library

Select the sprite you want to add the sound to.

Click the Sounds tab, and click Choose a Sound:

Sounds are organised by category, and you can hover over the icon to hear a sound. Choose a suitable
sound.

You should then see that your sprite has your chosen sound.
Add this code to play a sound and make the backdrop change colour when the player wins.

when I receive won

start sound drum machine

repeat 50

change color effect by 25

wait 0.1 seconds

clear graphic effects

Step 5 Multiple levels

So far, the player only has to remember a sequence of five colours. Improve your game by adding a score, and adding code
so that as the player scores points, the game moves to the next level and the colour sequence to remember becomes
longer.

Create a new variable called score.

Add a variable in Scratch

Click on Variables in the Code tab, then click on Make a Variable.

Type in the name of your variable. You can choose whether you would like your variable to be available to
all sprites, or to only this sprite. Press OK.

Once you have created the variable, it will be displayed on the Stage, or you can untick the variable in the
Scripts tab to hide it.

Based on the score, the game will decide on the length of the colour sequence. Start with a score (and a sequence length)
of 3.
 Add a block at the start of your character’s when flag clicked code to set the score to 3.

Instead of always creating a sequence of five colours, you now want the score to determine the sequence length.

Change the character’s repeat loop (for creating the colour sequence) to repeat score times:

repeat score

If the player repeats the correct sequence, you should add 1 to score, and doing so increases the length of the
next sequence. Add the following block to the character’s code at the point you know the sequence is correct:

change score by 1

I need a hint
You know the sequence is correct at the point when the game broadcasts the ‘win’ message.
Finally, add a forever loop around the code that generates the sequence, so that the game creates a new
colour sequence for each level. This is how your character’s code might look:

when clicked

set score to 3

forever

delete all of sequence

repeat score

add pick random 1 to 4 to sequence

switch costume to item length of sequence of sequence

wait 1 seconds

wait until length of sequence = 0

broadcast won and wait

change score by 1

Get your friends to test out your game. Remember to hide the sequence list before they play it!
Step 6 High score

Now save the high score so that you can play against your friends.

Add two new variables called high score and name to your project.

When the game ends because the player gets the sequence wrong, the game should check whether the score is higher
than the current high score. If it is, the game should save the score as the high score, and also store the name of the player.
Add code to your character sprite to store the high score. Also ask for the player’s name, and store it in the
name variable.

Create a high score in Scratch

It’s fun to keep track of a high score in a game.

Let’s say you have a variable called score, which gets set to zero at the beginning of each game.
Add another variable called high score.

At the end of the game (or whenever you want to update the high score), you’ll need to check whether you
have a new high score.

I need a hint
Here’s how your code for when the red button is pressed should look:
 when I receive red

if item 1 of sequence = 1 then

play drum item 1 of sequence for 0.25 beats

delete 1 of sequence

else

say Game over! for 1 seconds

if score > high score then

set high score to score

ask High score! What is your name? and wait

set name to answer

stop all

You need to add this new code to the character sprite for the other three colours too!
Can you see that the ‘Game over’ code for each of the four colours is exactly the same?
 say Game over! for 1 seconds

if score > high score then

set high score to score

ask High score! What is your name? and wait

set name to answer

stop all

If you need to change any of the ‘Game over’ code, for example to add a sound or change the ‘Game over’ message, you
have to change it four times. That’s annoying and wastes a lot of time.

Instead, you can define your own code block, and use it anywhere in your project.

Click on My blocks, and then on Make a Block. Call this new block Game over.
Add the code from the else block connected to the red broadcast to the Game over block so that it looks like
this:

define Game over

say Game over! for 1 seconds

if score > high score then

set high score to score

ask High score! What is your name? and wait

set name to answer

stop all
 Now remove the code that’s in the else block connected to the red broadcast, and add in the Game over block
instead:

when I receive red

if item 1 of sequence = 1 then

play drum (1) Snare Drum for 0.25 beats

delete 1 of sequence

else

Game over

Test your new block by playing the game and clicking the red button at the wrong point in the colour sequence.

Your new Game over block is a function, a little script that you can use anywhere you like in your code by adding the
Game over block in.
Also replace the code in the else block connected to the broadcasts for the other colours with your new Game
over block. Here is what the code for the blue message should look like

when I receive blue

if item 1 of sequence = 1 then

play drum (2) Bass Drum for 0.25 beats

delete 1 of sequence

else

Game over
Now add a sound that plays when the wrong button is pressed. You only need to add this code once in the Game
over block that you made, and not four separate times!

define Game over

start sound Cough1

say Game over! for 1 seconds

if score > high score then

start sound trumpet1

set high score to score

ask High score! What is your name? and wait

set name to answer

stop all
Step 7 Challenge: improve your game

Make more blocks

Do you see any other code that is the same for all four buttons?

when I receive red

if item 1 of sequence = 1 then

play drum (1) Snare Drum for 0.25 beats

delete 1 of sequence

else

Game Over

when I receive blue

if item 1 of sequence = 1 then

play drum (2) Bass Drum for 0.25 beats

delete 1 of sequence

else

Game over

Can you make another custom block that all buttons can use?
Another costume
Can you see that your game starts with your character showing one of the four colours, and that the character always
displays the last colour in the sequence while the player is repeating the colour sequence?
Can you add another plain white costume to your character, and add code so that the character displays this costume at
the start of the game and while the player is repeating the sequence?
Difficulty level
Can you allow your player to choose between playing the game in ‘easy mode’ (using just the red and blue colours) and
‘normal mode’ (which uses all four colours)?

If you want, you can even add a ‘hard’ mode, which makes use of a fifth drum!
Step 8 What next?

Try out the next project, Dodgeball (https://projects.raspberrypi.org/en/projects/dodgeball?utm_source=pathway&

utm_medium=whatnext&utm_campaign=projects), where you will make a game in which you have to avoid balls while
moving from platform to platform.

dodgeball game being played

Published by Raspberry Pi Foundation (https://www.raspberrypi.org) under a Creative Commons license (http

s://creativecommons.org/licenses/by-sa/4.0/).
View project & license on GitHub (https://github.com/RaspberryPiLearning/memory)